The present invention relates to meters, counters, printers and similar devices wherein a shaft carries one or more ring-shaped elements, particularly wheels, and the ring-shaped elements must be free to turn, at times, relative to the shaft or vice versa. Typical examples of devices to which the present invention pertains are odometers, paginators and apparatus for applying prices to items in supermarkets and similar establishments, i.e., devices which serve to apply or exhibit indicia in the form of numerals, letters and/or combinations of letters and numerals.
In devices of the above outlined character, the ring-shaped elements (e.g., the wheels of a counter) must be free to rotate with reference to the shaft or vice versa. For example, one wheel of a counter will turn through a small angle in response to a full revolution of the adjacent wheel, and so forth. As a rule, the internal surfaces of the wheels have angularly distributed sockets for detent elements which are yieldably mounted on the shaft to allow for rotation between the shaft and one or more wheels. In many presently known devices of the above described type, the detent elements are spring-biased balls which are urged into selected sockets of the adjacent wheels. It is also known to employ detent elements in the form of lamellae which are biased by rubber pads as well as in the form of pins having spherical heads and being biased into the sockets of the adjacent wheels.
A drawback of the above outlined and other known detent elements which couple a shaft to one or more wheels or similar ring-shaped elements is that their manufacturing cost is rather high and also that the assembly takes up a considerable amount of time. Thus, if the shaft carries several spring-biased balls or pins, its peripheral surface must be formed with a corresponding number of discrete accurately machined blind bores or holes. Moreover, the manufacturing cost of numerous springs, balls, lamallae, pins with spherical heads and like component parts is very high. Still further, one and the same shaft cannot be used with different types of ring-shaped elements, i.e., it is necessary to machine different series of shafts for each device wherein the axial length of wheels or analogous ring-shaped elements deviates from the axial length of such elements in another device. This will be readily appreciated since the spacing of holes for springs and balls in a shaft which is to be surrounded by relatively wide wheels must be different from the spacing of such holes or bores in the periphery of a shaft which is to support a set of thin wheels or like ring-shaped elements.